William durham sargent



(No Model.)

W. D. SARGENT.

BRAKE SHOE. No. 600,294.

Patented Mar. 8, 1898 Ntnn STATES I ATENT FFICE.

IVILLIAM DURHAM SARGENT, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE SARGENT COMPANY, OF SAME PLACE.

BRAKE-SHOE.

SPECIFICATION forming part of Letters Patent No. 600,294, dated March 8, 1898.

Application filed September 14, 1897. Serial No. 651,580. (No model.)

that class of brake-shoes in which the W631- ing or operative face of the shoe is a composition of comparatively soft friction-producing material molded, compressed, or otherwise secured in a metallic shell. There are numerous examples in the prior art of such compositions, and the use of some of them has proven very desirable both because of their frictional qualities, which reduces the pressure necessary with all metallic brakeshoes to produce the desired braking effect, and because such brake-shoes do not produce the rasping and squeaking noise when the brakes are applied such as commonly results in the use of metallic-faced shoes. Such shoes, however, have proven objectionable in a commercial Way, principally because of the weakness of the shoe and the rapidity of its wear, the compositions or combinations of material which form the body of the shoe greatly detracting from the strength thereof, while at the same time obviously offering less resistance to wear than would a plain metal shoe.

The prime object of this invention is to secure all of the advantages of a friction-producing-composition wearing-face and at the same time avoid the objections above cited.

Another object of this invention is to materially increase the strength and promote the longevity of brake-shoes having a friction-producing composition for their working faces and at the same time greatly increase the efliciency of such brake-shoes.

These and such other objects as may hereinafter appear, together with certain novel details in the construction of my brake-shoe, are illustrated in the accompanying drawings, in which Figure 1 represents a longitudinal section through a portion of a brake-shoe embodying my invention. Figs. 2 and 3 illustrate similar views of other forms of my invention. Fig. 4 represents a transverse vertical section on the line 4 at of Fig. 1. Fig. 5 represents a transverse section showing a modification, and Figs. 6 and 7 illustrate examples of the metallic inserts illustrated in the other figures of the drawings.

Similar reference characters indicate the same parts in the several figures of the draw- 1ngs.

In the practice of my invention, generally stated, I first prepare a shell or skeleton, preferably of cast metal, having the general shape and dimensions of the brake-shoe desired. Either in the act of casting the brake-shoe shell or after the casting is made I provide the shell with a series of foraminous sheetlike inserts spaced a suitable distance apart and arranged either longitudinally or transversely of the cavity in the shell and lying in a parallel plane with or at an angle to the wearing-face of the shoe. I then fill the cavity of the shell and of course the spaces between the foraminous inserts, as Well as the perforations in such inserts, with a frictionproducing compound in a plastic state, which compound may be allowed to set without pressure or may be compressed under any desired pressure in the shell. It may also be found desirable to place the foraminous insert in position and fill the spaces between them with the composition in building up the shoe and finally subjecting the Whole mass to powerful compression. These foraminous inserts serve numerous useful purposes, one of which is that they hold the mass firmly in position as against dropping out, cracking, or injury from blows during the life of the brake-shoe. Another purpose served by these foraminous inserts is that of greatly strengthening the brake-shoe as a Whole. Still another purpose served by these inserts is that of promoting the longevity of the shoe by providing the same with a wearing-surface which shall at intervals or continuously during the life of the shoe be of a composite character, consisting of the insert and the friction composition distributed substantially uniformly throughout the wearing-surface of the shoe.

Referring now by letter to the accompanying drawings, in Fig. 1 I have shown the inserts A as rigidly and permanently attached to the shell B in the act of casting the latter, the inserts being properly placed in the mold, so that at their ends, and sides too, if desired,

they will be embedded in the shell. Of course with such construction it will be necessary to fill the shellwith the plastic friction-producing composition 0. by pouring the same into the-shell and either allowing it to percolate through the interstices of the foraminous inserts and set without pressure or force the composition by pressure through the foraminous inserts and compacted in the shell by powerful compression.

In Fig. 2 the inserts A are simply sprung into the shell B at regular intervals, extending longitudinally thereof and lying in a plane parallel with the face of the brake-shoe, this latter arrangement being also true of the construction shown in Fig. 1. Inthis construction shown in Fig. 2 the friction-pro-- ducing composition 0 and the inserts may be placed in the shell ,in alternate succession, building the shoe up from the bottom by first filling the shell a desired depth with the composition, then springing in an insert, then filling in another layer of composition and springing in another insert, and so on until the shoe is complete. composition maybe allowedto set or be baked or forced into the shell under proper compression.

The only difference shown in the construction in Figs. 2 and 3 is that in the latter ledges or shoulders D are provided on the walls of the cavity in the shell B to receive and support the ends of the inserts A as against withdrawal or dropping out of the cavity, thus avoiding the necessity for permanently attaching the inserts to the shell by casting or otherwise or reliance upon the spring of the insert to retain the latter in proper position in the shell. Except for this difierence inconstruction everything I have said as to Figs. 1 and 2 applies to the construction shown in Fig. 3.

In Fig. 5 I have shown a transverse section of a brake-shoe embodying my invention in which the inserts A are shown as arranged upon edge longitudinally of the brake-shoe and lying in a plane at a right angle to the working face of the shoe. It is obvious without illustration that the inserts might be also arranged on edge, as shown in Fig. 5, but extending transversely instead of longitudinally of the brake-shoe.

In this case also the In Figs. 6 and 7 I have shown two wellknown forms of inserts, the former consistin g of the commercial product known as expanded metal and the latter consisting of an open-mesh wire-netting. The former is preferred because of the character of the metal usually employed in the manufacture thereof, which is best adapted for the purposes of a brake-shoe and which is best disposed for the purposes of promoting the strength,longevity, and effectiveness of the brake-shoe; but I desire to state that I do not wish to confine my invention to either of the forms of inserts illustrated in the drawings, for any foraminous insert which would subserve the intended purpose would fall within the contemplation of my invention.

As to the friction-producing composition used as a filling for the cavity in the shell of my brake-shoe, I have before stated that there are many examples of such compounds in the prior art, and I therefore do not desire to limit myself to any particular composition of material. The most satisfactory of such materials generally are combined iron-filings, asbestos, plumbago, and other materials with a binder variously combined according to the particular work to be performed by the brakeshoe, and indeed there may be other compositions of a totally difierent nature which would subserve the intended purposes of my invention; but all such compounds would fall within thepurview of my invention.

' Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is-

l. A brake-shoe comprising a shell, a series of foraminous inserts located in the cavity in said shell, and a filling for the cavity in said shell consisting of a friction-producing composition, substantially as described.

2. A brake-shoe comprising a shell, a plurality of foraminous inserts arranged in the cavity in said shell in planes substantially parallel with the face of the shoe and a filling for the cavity in said shell consisting of a friction-producing composition, substantially as described.

3. A brake-shoe comprising a shell, a plurality of foraminous inserts consisting of eX- panded metal located in the cavity in said shell and a filling for the cavity in said shell consisting of a friction-producing compound, substantially as described.

WILLIAM DURHAM SARGENT.

Witnesses:

JULEs N. RAYMOND, WM. 0. BELT. 

